1. Field of the Invention
The present invention relates to a method of and an apparatus for controlling the drying of a photographic material in which the photographic material is dried by a combination of a heat roller and warm air, the temperatures of both the heat roller and the warm air being relatively controlled.
2. Description of the Related Art
A photographic material, onto which an image has been exposed, is successively subjected to some processes such as developing, fixing, and washing by respective processing solutions such as a developing solution, fixing solution, and washing water. Thereafter, the photographic material is subject to drying in a drying section.
Usually, the drying section comprises a plurality of conveying rollers through which the photographic material passes with nip or without nip. Both surfaces of the photographic material contact the conveying rollers and the photographic material is conveyed by the driven conveying rollers.
Here, an arrangement of the drying section in which drying air blow ports are disposed between the respective rollers is known. When the photographic material passes between the rollers, the drying air is blown thereon from the blow ports. The photographic material is thereby dried by the drying air.
Recently, a request for reducing the entire processing time of the processing apparatus has been made, especially with regards to drying time. Accordingly, the drying efficiency of the apparatus must be increased. In order to meet this request, we have proposed an arrangement in which heat rollers have been used as the conveying rollers in the drying section so as to heat the photographic material and efficiently evaporate moisture contained therein.
Consequently, the moisture content of the photographic material, even if it exceeds the amount of saturated moisture immediately after processing, is efficiently evaporated from the photographic material heated by contacting the heat rollers and then the moisture evaporated from the photographic material is removed from the surfaces of the photographic material by drying air. Drying efficiency is thereby increased. Drying efficiency is further increased by repeating heating by the heat rollers and the blowing of drying air. Thus the entire processing time can thereby be reduced without reducing the time of the developing, fixing and washing processes.
However, in a drying device which uses a combination of such heat rollers and drying air, the temperatures of the heat rollers and the warm air which serves as drying air are irrespectively controlled. That is, the effectiveness for drying the photographic material (the effect which contributes to the drying of the photographic material, and hereinafter, will be referred to as relative "contribution" or "percent contribution") by the heat rollers and the drying air has not been taken into account. For this reason, when the temperatures of the heat rollers and the warm air are set while the surface temperatures of the heat rollers (and other rollers as well) are low, the relative contribution of the drying air needs to be raised by raising the temperature of the drying air because the drying ability of the entire drying section decreases. As a result, the capacity of a heater for heating the drying air must be increased. Moreover, heat resistance of the drying section and its peripheral components must be raised.
Further, when the relative contribution of the drying by the heat rollers is excessively high, the quality of the images may deteriorate due to drying irregularities or the like.